This invention relates to the communication of signalling activity information between coexisting communication support entities and, in particular, the interpretation of signalling activity information at a communication support entity.
An increasing number of modern devices are capable of radio communication using multiple communication technologies. For example, many laptops, PDAs and smartphones are capable of communicating via Bluetooth during a period in which they are also communicating via IEEE 802.11. This can lead to interference between the competing radio signals, resulting in a degradation of system performance. Interference can be especially acute when the two transceivers are operating in the same band or channel, as is the case with Bluetooth and IEEE 802.11, which operate in the Industrial, Scientific and Medical (ISM) frequency band.
One way of mitigating the effects of such interference is to arrange for the communication technologies to cooperate with one another with the aim of ensuring that only one communication technology is transmitting on a particular frequency, band or channel at a time. This cooperation is sometimes termed “coexistence arbitration” and may be achieved through the exchange of activity information between collocated transceivers. Based on the exchanged information a transceiver can choose to schedule its signalling activity so as to avoid collisions or temporal overlap with the signals of a collocated communication technology.
Multiple communication technologies can be collocated on a single integrated circuit. For example, an IC could support both 2.4 and 5 GHz IEEE 802.11 technologies. In other, multi-chip configurations, different chips may provide different communication solutions at a device. This is generally the case for devices in which Bluetooth and IEEE 802.11 coexist—one chip handles Bluetooth communications, and another handles the IEEE 802.11 communications.
In existing coexistence schemes, activity information signals may be exchanged between communication technologies, with each signal indicating that communication activity at the source of the signal will commence coincident with the signal itself, or a fixed time after the signal is received. In such schemes, the time at which the activity information signal is sent is tied to the time at which the communication activity is to occur.
There is therefore a need for a mechanism that allows the transfer of accurate future signalling activity information between communication technologies.